Device for regenerating foil webs or foil strips into a granulate

ABSTRACT

An apparatus for regenerating foil webs and foil strips to granulates, which comprises an extruder having its inlet fixedly connected to a funnel-shaped supply container and also having an outlet into which extends a worm with agitator, said worm tapering toward the interior of said extruder. Above said supply container there is arranged a grate roller and counter roller cooperating therewith for receiving material to be regenerated and diminuting said material and conveying it to said extruder, which in its turn passes the material received from said grate roller through a bath and drying device to a granulator and granulate packing device associated therewith.

United States Patent 191 Koch 1 1 July 10, 1973 [54] DEVICE FORREGENERATING FOIL WEBS 3,277,519 10/1966 Jones 425/315 X 0 O STRIPS N AGRANULATE 3,545,686 12/1970 Brown 3,551,943 [/1971 Staton et a1 425/308X Heinrich Koch, Jakobstr. 88, 52 Siegburg, Germany Filed: Mar. 4, 1971Appl. No.: 120,868

Foreign Application Priority Data Mar. 16, 1970 Germany ..P 20 12 344.8

US. Cl 241/93, 241/l01.5, 241/224 Int. Cl. 1302c 19/00 Field of Search241/34, 36, 63, 83, 241/91, 93, 101 R, 221, 222, 224, 225, 227; 425/71,202, 308, 315, 377

Inventor:

References Cited UNlTED STATES PATENTS Billingsley 18/125 H PrimaryExaminer-Granville Y. Custer, Jr. Attorney-Walter Becker [57] ABSTRACTAn apparatus for regenerating foil webs and foil strips to granulates,which comprises an extruder having its inlet fixedly connected to afunnel-shaped supply container and also having an outlet into whichextends a worm with agitator, said worm tapering toward the interior ofsaid extruder. Above said supply container there is arranged a grateroller and counter roller cooperating therewith for receiving materialto be regenerated and diminuting said material and conveying it to saidextruder, which in its turn passes the material received from said grateroller through a bath and drying device to a granulator and granulatepacking device associated therewith.

3 Claims, 4 Drawing Figures PATEME m 1 0 ms SHEEY 2 BF 3.

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SHiEIEBFB DEVICE FOR REGENERATING FOIL WEBS OR FOIL STRIPS INTO AGRANULATE The present invention relates to a device for regeneratingwebs or strips of foil to form a granulate. When producing andprocessing foil webs of synthetic material, rejects as well as waste areobtained. Such rejects and waste material can, however, be regeneratedto the starting material, i.e. a granulate, becuase the syntheticmaterial employed for the foils will during its regenerating process notlose its basic properties.

Various regenerating devices have become known by means of which it ispossible to regenerate rejects as well as waste. According to oneheretofore known ,device, a beater mill is used for regenerating thefoil material. In such beater mill the foil web or foil waste is crushedand subsequently is mixed in a dry mixer until due to the occurringfrictional heat a granular agglomerate is formed which can again be usedas starting material. The drawback of this heretofore known deviceconsists in that the crushing of the foil webs or foil waste in thebeater mill as well as the subsequent treatment in the dry mixer have tobe controlled with highest accuracy because, for instance,polyvinylchloride foils are extremely sensitive to an excessive heatdevelopment. Already when a slight excess temperature oc curs, chemicalreactions take place with these foils which change the character of thebasic material. Therefore, with this known device, especially the mixingprocess had to be controlled precisely by the respective operator.

For purposes of regenerating foils or foil waste it has also becomeknown to melt the foil waste material or the foils and subsequently tofurther process the same to the basic material. The melting of the foilwebs and foil waste can, however, be carried out only with suchsynthetic materials which do not lose their basic properties during themelting operation.

The drawback of the heretofore known devices for regenerating foil websor foil waste material of synthetic material consists primarily in thatit is not possible to carry out the work in a continuous operation noris it possible to carry out the operations without the presence ofskilled operators. Furthermore, the employed regenerating methods arenot feasible for all foils of synthetic material.

It is, therefore, an object of the present invention to provide a devicewhich will work automatically and in a continuous manner and which willbe independent of the kind of foil material employed.

This object and other objects and advantages of the invention willappear more clearly from the following specification in connection withthe accompanying drawings, in which:

FIG. 1 diagrammatically illustrates a regenerating device according tothe present invention.

FIG. 2 illustrates on a somewhat larger scale than FIG. I a portion ofthe extruder of the device of FIG. I together with the auxiliary devicesassociated therewith.

FIG. 3 represents a section through a grate roller for use in connectionwith the device of FIG. 1, said section being taken along the line IIIIII of FIG. 4.

FIG. 4 is a view of FIG. 3 as seen in the direction of the arrow A inFIG. 3.

The device according to the present invention is characterized primarilyby an extruder the inlet of which has fixedly connected thereto afunnel-shaped supply container into which extends a worm with anagitator which worm extends into the extruder inlet and tapers towardthe latter. The device according to the invention furthermore comprisesa grate roller which is arranged above the supply container or isfixedly connected thereto while there is also provided a counterpressure roller. Finally, the device comprises a water bath adjacent theextruder, a drying device, and a granulator with an adjacent granulatepacking device.

As charging device for the supply container there may, in addition tothe grate roller with counter pressure rollers, also be provided arotary trap connected through a conduit with a silo.

The grate roller with counter pressure rollers as well as the rotarytrap may be controlled in conformity with each other or independently ofeach other in order to make sure that during the regenerating treatmentof the foil webs or foil strips by means of the grate roller withpressure rollers the process can continue when the band or strip breaks.The invention furthermore provides a band or strip checking device,preferably in the form of a photoelectric cell which precedes the grateroller with counter rollers and by means of which in response to a breakof the band or strip material, the rotary trap will be made effective,and granulate will be fed from a silo. In this way it will be assuredthat the regenerating extruder can work without interruption. At theinstant at which the supply container is again filled with foil materialwhich has been pretreated by the grate roller with counter pressurerollers, the rotary trap is turned off. There also exists thepossibility of withdrawing the foil webs or foil strips not from a balebut directly from the calender. In order to assure that the entireoperation can be carried out in a continuous manner, it is suggested,according to a further development of the invention, that thewithdrawing speed of the grate roller with counter pressure rollers isadapted to be controlled driectly by the calender by means of anystandard auxiliary devices.

Rferring now to the drawings in detail, a regenerating plant or devicefor the preparatory treatment of webs of foil of synthetic materialaccording to the present invention comprises a regenerating extruder 1having an inlet 2 to which is firmly connected a funnel-shaped supply orstorage container 3. The connection between the extruder l and thesupply container 2 is effected by a flange-like intermediate member 4.In the container 3 there is provided a worm 5 which tapers toward theextruder inlet 2. The worm 5 has an upwardly extending shaft 6 on whichis mounted an agitator mechanism 7 for rotation with the worm 5. Worm 5together with agitator mechanism 7 is driven by a motor 8 through theinterposed transmission 9. To safeguard the motor 8 in case the worm Sis overloaded, there is provided a limit switch 10 which in suchinstance will turn off the motor 8. The foil material to be regeneratedin the extruder l is first pretreated in a grate roller 11 with pres- Isure roller 12. The pretreatment of the foils l3 entering in thedirection of the arrow F is effected in such a way that by means of thegrate roller 11 the foil web or foil strip is cut into individualsections while in view of the continuous winding-up of the web or stripmaterial in cooperation with the heated grate bars, the cut off orseparated sections are pressed against each other layer for layer andare fused to each other at the cutting edges. The thus fused togethersections are through the free grate cross-sections 14 pressed in theform of a strand into the inner chamber 15 of the grate roller and fromthere are conveyed into the supply container 3 by standard tearing andconveying means. For purposes of checking the feeding of the material tobe processed to the grate roller, a photoelectric cell 16 is providedserving as band checking means. The photoelectric cell 16 is coupled tothe rotary trap 17 in such a way that when the band or strip breaks ortears off whereby automatically the supply of pretreated foil materialto the container 3 is interrupted, the device 17 is automatically turnedon and conveys through a pipe line 18 connected to a non-illustratedsilo, for instance, polyethylene granulate or a polyvinylchloridemixture into the container 3. In this way it will be assured that theworm of the extruder 1 can always sufficiently be supplied withsynthetic material so that a burning of the material will be prevented.As soon as the web or strip of foil material is again threaded into thegrate roller 11, the device 17 will turn off.

If a disorder occurs in the opeation of the plant or calender or if achange in the calender is to be effected, the extruder has to be stoppedfor a shorter or longer period of time. During a short interruption, thedevice 17 feeds corresponding PVC-material to the extruder. If a longerstandstill period of the extruder is necessary, there exists the dangerthat the PVC-material in the extruder will in view of the longer stay bedestroyed as far as its chemical structure is concerned and can nolonger be used. In such an instance, instead of the PVC- material, highpressure polyethylene is supplied by the device 17 which material isnon-sensitive against a longer stay in the worm. After the calender hasagain been started and strip material is again pressed into the extruderwhile the worm is continuously operating, the oncoming PVC-material willpress the polyethylene in the worm out of the latter. After a shortperiod of operation, it is again possible to process polyvinylchloridefoils in a continuous operation.

The material regenerated in the extruder l is discharged through anozzle head 19 in the form of a band and is then passed through a waterbath 20. Subsequently, the thus regenerated material is conveyed over adrying path 21 and from there is passed into a granulator 22 which iscoupled to a packing or a wrapping device which automatically closes thesack or bag 23 filled with granulate.

If the strip material directly coming from the calender is processed inthe plant according to the present invention, the strand dischargedthrough the nozzle head 19 of the extruder 1 can be directly conveyed tothe calender for the purpose of making new foils.

As shown more specifically in FIG. 4, the grate roller 11 is journalledat 3' by means of a shaft 22. Grate roller 11 comprises bars 24 which attheir surface 25 have a sharp edge 26 and which have a cross-sectionthat increases toward the inner chamber 15 of the grate roller. Theenlargement of the cross-section of the grate bars 24, as isparticularly clearly shown inFlG. 3, extends in this embodiment over acertain length only and then remains constant. Regardless of whether theincrease in cross-section of the bars of grate roller 11 toward theinterior 15 of the grate roller is continuous over the entire thicknessof the roller or only over a portion thereof and then is constant, freepassage 28 are formed which in view of the configuration of thecross-section of the bars 24 of the grate'roller are funnel-shaped ortaper. As will be evident from FIG. 4, the bars or webs are so arrangedwith regard to each other that free passages of square cross-section areformed. The arrangement of the bars 24 may, however, also be such thatpassages of a different cross-section, for instance, rectangular, ovalor circular cross-section, are formed. The rectangular or squarecross-section, however, is preferred. The pressure rollers 12 cooperatewith the grate roller 11 and are offset with regard to each other by 120as is best seen in FIG. 3. There exists, of course, also the possibilityto employ only one or more than three pressure rollers 12. A conveyor,preferably a worm 30, cooperates with the grate roller 11. Worm 30extends into the interior 15 of the grate roller and has its largestdiameter D so dimensioned that a free space 31 is formed between theworm 30 and the inner configuration 11a of the grate roller.

The operation is as follows: The web of foil 13, for instance, a web ofpolyvinylchloride, is wound onto the grate roller 11, and in view of thecontinuously increasing layer thickness is pressed against the edges 26of the bars 24 of the grate roller whereby the foil web is cut intoindividual sections. This cutting or division is facilitated by aheating effect produced by the bars 24. Simultaneously with theseparation into individual foil sections at the edges 26 of the webs orbars 24, a fusing of the individual superimposed layers takes placewhich is aided by the corresponding configuration of the bars 24 and theformation of tapered free passages 28. During the continuous winding-upof the foil web 13 onto the grate roller 11 and the thus inherentseparation of the web 13 into separate sections, individual strands 34(FIG. 3) are formed which move through the free passages 28 of the grateroller 1 1 into the interior chamber 15 of the grate roller. Here theindividual strands are grasped by the worm 30 and are divided intoindividual package-like structures and are subsequently conveyed to asupply or further processing station.

The heating up of the grate rollers may be effected in any suitablemanner. For instance, the bars 24 may be provided with bores 35 throughwhich heated-up oil is passed or into which heated-up rods or wiresextend. The temperature of the grate bars 24 is such that the working ofthe foil is effected at temperatures of from C to C.

In this way foil bands of any width may be processed. Prior to the bandshitting the grate rollers 11, the bands 13 must be laterally gathered ifthey are wider than the width of the grate roller. These steps, however,can be easily effected.

It is also advantageous that theentire winding-up and separating processcan be so coupled with the discharge step that no more material isdischarged than is wound up and divided into sections.

The device according to the present invention for refining foil webs orfoil strips to make a granulate has the advantage that the entireregenerating process can be carried out in a continuous manner and isentirely or partially automatic. The device according to the presentinvention can therefore be supervised by a single operator. Moreover,the plant or device according to the present invention is simple and caneasily be checked so that no skilled personnel is necessary.

Moreover, the device according to the invention can be employed not onlyby producers of foils but also by users of foils or in plants whichfurther process foils. When the device is used in a foil manufacturingplant,

the device according to the present invention may be connected directlyto a calender while the band speeds can be tuned to each other, When thedevice is used in plants which further process the foils, the foil websor strips may be rolled to form bales and from there may be conveyed tothe regenerating device.

It is, of course, to be understood that the present invention is, by nomeans, limited to the particular con struction shown in the drawings butalso comprises any modifications within the scope of the appendedclaims.

What I claim is:

1. An apparatus for washable preparation regenerating foil webs and foilstrips to granulates, which includes in combination: extruder meanshaving inlet means and outlet means, funnel-shaped supply containermeans connected to said inlet means, worm means rotatably arranged insaid container means and having its windings decrease in diameter in thedirection toward the inlet means of said extruder means, said worm meansextending into said inlet means, shaft means coaxial with and rotatablyconnected to said worm means and provided with agitator arms forcooperation with said worm means, motor means drivingly connected tosaid shaft means for rotating the same and thereby said worm means,grate roller means arranged adjacent said container means for receivingweb and strip material and diminuting the same and conveying it intosaid container means, said grate roller means having a peripheralsurface formed as a grid with openings therethrough bordered by cuttingedges, and having central means to convey material to said supplycontainer means, and pressure roller means on the periphery of saidgrate roller means operating to press strip material wound on said grateroller means against said cutting edges and through said openings tosaid central means.

2. An apparatus in combination according to claim 1, which includesrotary trap means having inlet means and having outlet means locatedabove and for connection, with said container means for feedingsynthetic material to said container means in case of a standstill ofsaid grate roller means while said worm means is operating.

3. An apparatus in combination according to claim 2, which includeselectric control means adjacent the feeding path of material to beregenerated leading to said grate roller means for detecting anaccidental break in the continuous supply of the material to beregenerated to said grate roller means, and means operatively connectingsaid control means with said rotary trap means to respectively activateand de-activate the latter in response to an accidental break in andreestablishment of the continuous supply of the material to beregenerated to said grate roller means.

1. An apparatus for washable preparation regenerating foil webs and foilstrips to granulates, which includes in combination: extruder meanshaving inlet means and outlet means, funnel-shaped supply containermeans connected to said inlet means, worm means rotatably arranged insaid container means and having its windings decrease in diameter in thedirection toward the inlet means of said extruder means, said worm meansextending into said inlet means, shaft means coaxial with and rotatablyconnected to said worm means and provided with agitator arms forcooperation with said worm means, motor means drivingly connected tosaid shaft means for rotating the same and thereby said worm means,grate roller means arranged adjacent said container means for receivingweb and strip material and diminuting the same and conveying it intosaid container means, said grate roller means having a peripheralsurface formed as a grid with openings therethrough bordered by cuttingedges, and having central means to convey material to said supplycontainer means, and pressure roller means on the periphery of saidgrate roller means operating to press strip material wound on said grateroller means against said cutting edges and through said openings tosaid central means.
 2. An apparatus in combination according to claim 1,which includes rotary trap means having inlet means and having outletmeans located above and for connection with said container means forfeeding synthetic material to said container means in case of astandstill of said grate roller means while said worm means isoperating.
 3. An apparatus in combination according to claim 2, whichincludes electric control means adjacent the feeding path of material tobe regenerated leading to said grate roller means for detecting anaccidental break in the continuous supply of the material to beregenerated to said grate roller means, and means operatively connectingsaid control means with said rotary trap means to respectively activateand de-activate the latter in response to an accidental break in andre-establishment of the continuous supply of the material to beregenerated to said grate roller means.